Is There A Lifetime MPG Reading?

not if you don't track it on one of the meters. that's what i did with my pip, but mpg is all over the place based on how much you plug in and not really meaningful

 

i'm sure it's in toyotas black box, but it's proprietary

 

I think it's a yes/no type answer.

You have 3 choices for how to display mpg:
1. Trip - This automatically resets every time you start the car.
2. Tank - This automatically resets every time you refuel.
3. Total - This should be a lifetime reading, but I can't guarantee it persists if you disconnect/drain the battery.

 

I have been using an iOS app OBD fusion and there is a PID(Parameter ID) called Total Fuel Economy. I don't think it resets with the trip odometer or refueling. I have yet to figure out where the number is coming from or how it is calculated.



My most recent number I have a record of is 330.4 mpg which seems too high. Haven't investigated too vigorously but I am pretty sure it is not an accurate lifetime measurement of mpg. I have done one road trip where I used about 24 gallons of gas roundtrip and if it was correct that would mean that I have only added 8 gallons of gas to drive ~10000 miles. I know I have filled up more than 5 times so more likely real lifetime mpg would be half that.